Complementary dual antenna system

Abstract

The present invention provides a dual antenna system where a first antenna element has a metallic surface with openings that are resonant at frequencies other than the operating frequency of a second antenna element. The openings are sized such that the metallic components are relatively transparent at and near resonant frequencies of those openings. According to the present invention, the resonant frequencies of the openings may be the transmitting or receiving frequencies of the second antenna element, or of nearby antennas.

What is claimed is:  
     
       1. A complimentary dual antenna system comprising: 
       a first antenna comprising at least one first element on a structure for transmitting and receiving signals within a first frequency band;  
       a second antenna comprising at last one second element spaced apart from said at least one first element on the structure for transmitting and receiving signals within a second frequency band;  
       said first antenna having a first frequency selective surface, said first frequency selective space having a resonant grid pattern formed by the said at least one first element, wherein each of said at least one first element is tuned such that the first element is resonant and transparent at a frequency within said first frequency band and reflective at a frequency within said second frequency band; and  
       said second antenna having a second frequency selective surface, said second frequency selective surface formed by said at last one second element, said at least one second element each comprising a resonant opening tuned such that the said resonant opening is resonant and transparent at a frequency within said second frequency band and reflective at a frequency within said first frequency band.  
     
     
       2. The complementary dual antenna system as in  claim 1 , wherein each of the resonant openings have a length which is optimized to reduce the radar cross-section of said second antenna at a frequency within said first frequency band. 
     
     
       3. The complementary dual antenna system as in  claim 1 , wherein a separation between each of the resonant openings is optimized to provide a maximum bandwidth to said second frequency band. 
     
     
       4. The complementary dual antenna system as in  claim 1 , wherein said second frequency band is the L-band frequency range. 
     
     
       5. The complementary dual antenna system as in  claim 1 , wherein said resonator elements are selected from the group consisting of rings, cross dipoles, square loops, Jerusalem Crosses and tripoles. 
     
     
       6. The complementary dual antenna system as in  claim 1 , wherein said complementary dual antenna system is constructed as a decal. 
     
     
       7. The complementary dual antenna system as in  claim 1 , wherein said plurality of resonant openings are complementary to said resonant dements.